These notes give a beautiful exposition of the theory of representations of
the group ${\rm GL}(2,K)$, where $K$ is a finite field. In
71 well-organized pages, the author manages to cover a remarkable amount of
material clearly, concisely, and with many details. The table of contents goes
like this:Preliminaries (induced representations of finite groups and the
conjugacy classes of ${\rm GL}(2,K)$, etc.); The representations of
${\rm GL}(2,K)$ (inducing representations from the upper triangular
subgroup, construction of the cuspidal representations of
${\rm GL}(2)$ via characters of the quadratic extension of
$K$, the small Weil group and the small reciprocity law);
$\Gamma$-functions and Bessel functions (Whittaker models,
computation of $\Gamma$-factors, and computation of the character
table for ${\rm GL}(2,K)$).
The reviewer heartily recommends these notes for anyone interested in
either entering this research area or teaching a self-contained introduction
to the theory of group representations. Although many of the proofs given
exploit the fact that $K$ is finite, in presenting the material the
author definitely has in mind the current research being done in the theory of
(infinite-dimensional) representations of ${\rm GL}(2)$ (and more
general groups) over a local (as opposed to a finite) field $K$. -- Stephen Gelbart, Mathematical Reviews